Sunlight Creates Current

Photovoltaic (PV) cells transform solar energy directly into electric energy. The photoelectric effect was discovered by French physicist Alexandre Becquerel in 1839. He found that certain materials, when exposed to light or heat, release electrons, creating a flow of direct current. Semiconductors like silicon, a natural component of sand and gravel, are particularly suitable. Each thin, blue-tinted PV cell is cut from a single silicon crystal or a block of crystals. The first practical application came in the 1950s when NASA used PV cells to supply power to its satellites. Today, PV cells are in use around the world. Panels currently on the market have an energy-conversion efficiency of between around 15 and 25 percent and are easy to combine into a large array to create PV power plants.

Scientists and technicians are working hard to reduce the modules' production costs and to increase their energy-conversion efficiency. Some panels in development reaching up to 43 percent efficiency.